The invention relates to a vacuum packaging machine for the production of sealed packages from a first packaging material web having printed marks thereon and a second packaging material web. The machine has at least one deep drawing station which is movable in the longitudinal direction. The deep drawing station includes an upper processing unit and a lower processing unit adapted to perform a reciprocating movement with respect to each other, whereby the first web is fed responsive to printing marks relative to the forms fabricated out of the second web in the deep drawing station.
Material webs suitable for packaging are, as a rule, light flexible materials. The adherence to precise tolerance limits of printing marks is possible only with great technical effort. With typical commonly available packing material webs a tolerance range of .+-. 1% is observed. Known prior art packaging machines work acceptably when, at best, a tolerance of 0.6% occurs. If the spacing of the printing marks is too small the packaging material web is stretched. If, on the other hand, the spacing of the successive printing marks is greater than necessary, the entire printing mark control fails, because the sealing already results as soon as the next performed form is deposited in the sealing station and independent of the next printing mark. The printing marks appear continuously delayed in the course of sequential sealing and there occurs no more adjustment whatever to the marks.